The invention relates to a fuel composition and in particular to such a liquid composition to be burned in an engine such as an internal combustion engine, e.g. a petrol or Diesel engine or any engines designed to perform with liquid fuels.
It is well known that liquid fuels when burned in an internal combustion engine can give rise to pollution and other undesired side effects. Numerous proposals have been advanced to reduce these side effects and enhance efficiency, e.g. miles per gallon. It has been realised that surfactants can play a useful role in this context but so far as we are aware none has satisfied the modern commercial criteria. It is one object of this invention to meet the need.
In one aspect the invention proves a fuel composition including a fuel miscible additive selected to solubilise the fuel and the additive and any water present to form a clear homogenous composition.
The preferred additive of this invention is a non-ionic surfactant and preferably a blend of surfactants. It is a preferred feature of this invention that the surfactants be selected by their nature and concentration that the additive (as well as any water or other non-fuel liquid present) be solubilised within the fuel. For this purpose it is convenient to have regard to the hydrophilic-lipophilic (HLB) of the surfactant, the value being calculated according to the expression.   HLB  =                    mol        .                  xe2x80x83                ⁢        wt            ⁢              xe2x80x83            ⁢      of      ⁢              xe2x80x83            ⁢      hydrophilic      ⁢              xe2x80x83            ⁢      chain      xc3x97      20              total      ⁢              xe2x80x83            ⁢              mol        .                  xe2x80x83                ⁢        wt            
The values will depend on the length of the hydrophilic chain, typically an ethoxylate chain. The length of the chain will increase the extent of solubilisation because of a greater ability to solubilise.
Normally a blend of surfactants is preferred, preferably by selecting one appropriate to the fuel, say 10 to 18 for hydrocarbon fuel, most preferably 13. In the case of an alcohol the HLB value of the surfactant is between 3 and 7, most preferably about 4. But the addition of surfactants normally create ratios of 1:1 or high volume emulsions or 5:1 ratios when the solubalisation is required at 1:100.
The invention has the ability to unify the HLB requirements of any liquid fuel which in turn allows for one dose to be used in any fuel from C5 carbon chains up. The benefit being the amount of treatment directly related to the co-solvency ability (as per enclosed charts). The charts show three different combinations of additive allowing a cost comparison to performance requirements.
The monolayer aspect of the invention requires the concentration of the additive to be very low, typically of the order of 0.5-1:1000, preferably about 1:1000, most preferably 1:1200 there appears to be no technical or economic benefit in adding more unless a co-solvent duel action is required, when the priority will be dosage against performance.
The additive preferably comprises of the following:
an oil soluble ethoxylated alcohol
a super diethanolamide
a 7 chain ethoxylated fatty acid
The three ingredients must be added as per fuel and molecule production process.
Preferably the ethoxylate of the fatty acid makes up about 25% by volume of the additive and further preferably the alcohol ethoxylate comprises 50% by volume of the additive.
An additive of the invention may be added to a hydrocarbon fuel, e.g. Diesel or petrol or alcohol which may or may not be contaminated with water. The invention is seen to particularly good effect when added to synthetic fuels based on low fraction oils.
In another aspect the invention provides a fuel composition comprising a light weight fraction and including an additive miscible with the fuel selected to solubilise the fuel and the additive and any water present to form a clear homogenous composition.
The presence of the additive of the invention ensures that the fuel composition forms a consistent stable homogenous composition and creates a monolayer simoultenously a result of which leads to a better more complete burn which reduces pollution and increases miles per gallon.
As a result a blended fuel, particularly alcohol based, is able to combust more precisely with a cooler charge to reduce the iron-formates present form the aldehyde peracids and peroxide reactions normally attributable to engine degredation.
In another aspect the invention provides a method of forming a stable composition comprising adding the three specified ingredients, e.g. as an additive as defined to a fuel in a volume ratio of about 0.5-1:1000. Preferably the addition ratio is about 1:1000, most preferably about 1:1200.
A method of running an engine adapted to use a alcohol-based fuel, comprising adding to the fuel a miscible additive selected to solubilise the fuel and the additive so eliminating the deposit of by-products formed during the combustion of the fuel.
Fuel Production Process
1. Check water contamination by Karl Fischer and estimate volume of H2O in enduser tank.
2. Select from Stabiliser Charts the correct formula taking into consideration costs and treatment ratios.
3. When percentage of stabiliser is assessed blend necessary components as per chart and dose accordingly blending the molecule into the fuel and not mixing it.
Molecule Production Process
1. After correct selection of Super Amide blend at P.I.T. (Phase Inverse Tension) (55-58xc2x0 C.) the Alcohol, the Ethylene Oxide.
2. Blend 1 with the *Super Amide Chosen at P.I.T.
3. Blend Fatty Acid with Ethylene Oxide and blend with 2 at P.I.T.
4. Resulting in a total blend of Alcohol Ethoxylate. Which must at least be 50% of the total weight of the molecule with equal parts of Super Amide and Fatty Acid Ethoxylate to achieve 100%.*
*Super Amide MUST be blended with either Fatty Acid Ethoxylate or Alcohol Ethoxylate 
*Although a 50/25/25 blend in theory may not be the correct balance for a polymer, margins have to be taken into consideration for alien components such as Free Amines, Free PEG""s, Free Esters and Isomers which are all present during this process. The molecular weight of the two tails invariably balance at this procedure. 
Although the example stock solution is suitable for minimal water contamination problems the preferred alcohol ethoxylate will be straight chained primary linear and 3 mols of EO per.mol of alcohol as the precision in calculation is much more precise and the absorbant powers of the micelle is increased with the extra additions of ethoxylates. The primary and linear alcohol must be a minimum of 80% w/w as the balance of predominantly isomers are considered a contaminant and not helpful to the ethoxylation process.
The diethonanolimide should be a super amide which is identifyable as having a ratio of 1:1 fatty acid to diethanolamine as the 2:1 ratio contain 10% free amine esters and the nature of process allows this contamination which is not helpfull to the balancing of the polymer.
The fatty acid is preferably a C14 acid and is not manufactured by polyethylene glycol method as the free PEGS inhibit the ethoxylation process and upset the HLB balance.
In order that the invention may be well understood it will now be described by way of illustration only with reference to the following example.